337 research outputs found
Performance of Flexure-Controlled Reinforced Concrete Structural Walls Under Sequential Fire-Earthquake Loads
The performance of reinforced concrete (RC) structural walls under individual hazards has been well studied. However, little is known regarding the behavior of RC structural walls under sequential hazards. The research presented here seeks to address the performance of RC structural walls under sequential fire-earthquake loads (both post-earthquake fire and post-fire earthquake).
Longer burn times of post-earthquake fire and initial seismic damage can have significant structural impacts on RC structures which are usually considered to have superior performance in a fire. An 8-inch wall with characteristics representative of typical construction in seismic regions was utilized as the basis of the simulations. The wall with non-uniform layout of reinforcement provides a complex deformed shape under fire. Individual typical earthquake damage states were introduced to the wall to assess impact on fire resistance. The fire resistance of a wall was discussed according to thermal-insulation and load-bearing criteria in codes. The results show that crack does not impact the fundamental response of a wall under fire while cover loss decreases its load-bearing capacity significantly. Moreover, the location of cover loss has remarkable impact on the deformed shape of a wall and its load-bearing fire resistance. While the thermal-insulation capacity decreases below code requirements, the load-bearing fire resistance of earthquake-damaged walls is still acceptable.
Another potential but infrequently studied hazard is the post-fire earthquake scenario. The impact of fire damage on the earthquake behavior of RC walls is not well understood, which leads to some safety concerns in earthquake after fire or aftershocks after post-earthquake fire. A simulation procedure combining SAFIR and OpenSees is proposed and validated for the PFE analysis of RC structural walls. Based on the validated the simulation procedure, a parametric study on the PFE performance of RC walls was conducted. Results indicate that fire damage decreases the load-bearing capacity and stiffness of RC walls under reversed-cyclic loads while fire damage decreases the deformation capacity in most cases. Severe fire exposure may shift damage from the boundary element to the web. Wall characteristics which significantly impact the residual wall response quantities are wall thickness, boundary element length, and axial load ratio. In addition, a framework for simplified nonlinear modeling was proposed for the PFE performance of RC walls. The models are defined by modification factors that account for the change in wall response relative to that of a wall without fire damage. Modification factors, established from the results of the parametric study, are a function of fire damage indices that account for the effect of fire on the material properties of steel and concrete. Results indicate that the model is generally able to predict the response of a fire-damaged wall
EVALUATION OF PRE-HARVEST SCREENING FOR ANTIBIOTICS AND FLUNIXIN MEGLUMINE IN CATTLE
Many antibiotics and medications used in the treatment of animals have a withdrawal time; residues are a concern for the meat industry. The most recently published 2009 USDA-FSIS Residue Program Data Report listed 135,389 Inspector-In-Charge-Generated (IICG) residue samples from 43,142,500 beef and dairy cattle inspected that year at harvest (USDA-FSIS 2009a). Of these samples, 1306 contained violative antibiotic residues and 327 violative flunixin meglumine residues. Two classes of antimicrobials comprised over half of the documented violative antimicrobial residues (beta-lactams that include ceftiofur and sulfa drugs that include sulfadimethoxine). While the violative residue rate seems small, violative residues are unacceptable. Management of carcasses that contain violative residues is costly to the USDA, the meat packing industry, and the producers involved.
There is no preharvest or ante-mortem screening test currently available that mirrors the antibiotic screening test used by the United States Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) in beef and swine packing plants (USDA-FSIS Notice 39-09). Adapting the test currently used by the USDA-FSIS to screen for antibiotic residues in tissue or used by the Food and Drug Administration (FDA) to screen for drug residues in milk would make it possible for producers and veterinarians to identify or predict livestock that might be considered a high risk for containing a violative antibiotic residue in tissue. In addition, there is no preharvest screening test currently available to detect violative residue levels of flunixin meglumine and ceftiofur in cattle prior to market (Damian, 1997).
A simple, cow-side test for the presence of drug residues in live animal fluids would provide useful information for tissue drug residue avoidance programs. This work describes adaptation and evaluation of rapid screening tests to detect drug residues in serum and urine. Medicated herd animals had urine, serum, and tissue biopsy samples taken during drug treatment. Samples were tested by rapid methods and high-performance liquid chromatography (HPLC). The adapted microbial inhibition method, kidney inhibition swab (KIS®) test, was useful in detecting sulfadimethoxine in serum and successfully predicted proper drug withdrawal in the kidney by HPLC, 5 to 6 days post treatment. The lateral flow (LF) screening method for flunixin and beta-lactams adapted for urine was useful in predicting flunixin in the liver detected by HPLC, 96 hours post-treatment. The same adapted methods were not useful to detect ceftiofur in serum or urine relative to the recommended tissue withdrawal time after ceftiofur treatment. These anti-mortem screening tests demonstrated that the selection of method used, and whether urine or serum are tested, will vary based on drug used and should be based on animal treatment history if available. The live animal tests demonstrated the potential to allow verification that an individual animal is free of drug residues before sale for human consumption.
Advisor: Dee Griffi
Work process knowledge in Scottish visitor attractions
Work process knowledge (WPK) is a concept for systems-level knowledge of the workplace and has been shown to be most important in organisations requiring multi-functional working. Most of the previous body of knowledge on WPK has focussed mainly on manufacturing industries; there has been less investigation of WPK in the service sector and none in the visitor attraction (VA) industry, an important employer in Scotland. The VA industry is extremely dynamic and many businesses are rapidly moving towards multi-functional team working, driven by an urgent need to develop quality, customer-focussed strategies to survive in an over-supplied and very competitive market. This study identifies the nature of WPK in Scottish VAs, what relationship WPK has to customer service, how WPK in this service sector differs from selected published studies in manufacturing and other service sector contexts and what factors affect the development of WPK in VAs.
Following recruitment of a number of VAs using an online questionnaire and subsequent site visits, six sites were selected for case study, on the basis that they demonstrated most evidence of multi-functional working and staff with developed WPK. The research design was comparative case studies of the work processes and knowledge within these six VAs, based on a social constructivist framework, using the methods of key informant interviews and shadowing.
Although these six sites represent a cross-spread of attractions in terms of types, location and size, they nonetheless show strong similarities in their basic business structure. The data show that WPK is an essential element of workers’ roles and a vital requirement in providing good customer service. Although VA managers do not use the term ‘work process knowledge’, they nonetheless recognise the importance of having staff with a wider view of their business and are actively encouraging its rapid development. Multi-functionality and job rotation are main ways of developing WPK but sites also use key workers with job roles that help develop high levels of WPK, who are then used as a staff resource.
The main factor contributing to the development of WPK is communication, especially of systems-level information. Cultural information-sharing is an essential pre-condition for the development of WPK in this context. Other determining factors are flexibility, employee biographies, seasonality issues, how weddings and functions are handled on-site and the size and complexity of the site. WPK is the foundation on which good customer service is based and elements of it deliver customer service. It is the closely integrated nature of the employee-customer relationship that has such a profound effect on WPK development in this service sector industry and is essentially what differentiates it from previously published studies. The identification of the customer as a hitherto unrecognised key driver of WPK is the most important contribution to knowledge made by this work
Contact cooling and its effects on manual dexterity
In industry, it is common for workers to be exposed to a variety of cold surfaces including
machinery parts, walls and tools that have cooled to ambient conditions or are cooled by
the production process. Although there is legislation and there are guidelines to protect
workers and minimise safety risks in environments where there may be hot surfaces (skin
burns; EN 563:1994), this is not the case for environments containing cold surfaces.
It was hence decided by the European standardisation organisation CEN that a standard
should exist to outline the risks associated with contact with a cold material in terms of
skin damages, discomfort and effects on manual dexterity.
Data was collected for the development of a cold surfaces standard (European Union
project SMT4–CT97–2149). The standard should provide information on the relationship
between contact material type, surface temperature and the subsequent risk of pain,
frostbite and manual dexterity deficits after prolonged exposure.
Further research related to this standard was performed and is described in this thesis. [Continues.
Switching patients from other inhaled corticosteroid devices to the Easyhaler(®) : historical, matched-cohort study of real-life asthma patients
Peer reviewedPublisher PD
The Membrane as a barrier or target in cancer chemotherapy
The overall aim of the project was to investigate the role of the cell membrane as a barrier and/or target for drug action and relate this to the development of strategies for
overcoming multiple drug resistance (MDR).
The effects of doxorubicin on various bacterial strains expressing different levels of anionic phospholipid were compared. Giowth of wild-type Echerichia coli (E. coli) strain MRE600 was severely affected up to 9 hours following doxorubicin treatment (15uM), but resistance occurred after 9 hours. E. coli strain FIDL1 1 was resistant to doxorubicin (1 O0piM) over 9 hours, however, increasing the anionic lipid content showed little difference in sensitivity.
The mouse mammary tumour cell line (EMT6-S) and MDR sub-line (EMT6-R) were characterised with regard to growth kinetics, susceptibility to doxorubicin and membrane lipid composition. The log phase doubling times (h) were found to be 21.8 (EMT6-S)and 25.0 (EMT6-R) and the IC 50 values for doxorubicin to be 2.2 x 10-8 M and 1.8 x 10-6 M for EMT6-S and EMT6-R cells, respectively. No difference was observed between the phospholipid profiles of the two cell lines and total fatty acid composition was similar, however, the level of linoleic acid appeared to be higher in the resistant cells.
The photocytotoxicity of the cationic dyes methylene blue (MB), toluidine blue (TBO) and Victoria blue BO (VBBO) against the EMT6 cell lines was compared to the cyotoxic effect of doxorubicin and cis-platinurn. The cytotoxic effect of VBBO was enhanced 10-fold by illumination (7.2 J cm2) in both EMT6-S and EMT6-R cells. In order to overcome resistance, however, the EMT6-R cells required a 10-fold greater level of the dye than the parental cells to reach an IC50 value. By contrast, doxorubicin required almost a 100-fold increase in concentration to overcome this resistance.
Pre-treatment of EMT6-S and EMT6-R cells with low concentrations of VBBO resulted in a 2-fold increase in doxorubicin toxicity in both cell lines. Pre-treatment with MB and TBO resulted in a 1.4-fold and 2-fold increase in doxorubicin toxicity, respectively, in the sensitive cells, increasing to 2-fold and 3-fold, respectively in the resistant cells.
Glutathione (GSH) depletion of EMT6-S and EMT6-R cells did not enhance the photocytotoxicity of VBBO, suggesting that the primary site of action of VBBO is at an intracellular site not protected by GSH or that the mechanism of action is not via the in situ generation of singlet oxygen. Addition of the chemosensitizer, verapamil (7gM), increased the efficacy of doxorubicin by 2-fold in EMT6-S cells and by 18-fold in EMT6-R cells. By contrast, the presence of verapamil did not increase the cytotoxicity of YBBO in either cell line.
A series of compounds, PVB, MVB and MOVB, based on the skeleton of VBBO was examined. VBBO was found to be the most effective photosensitizer. The rate of uptake for VBBO, MVB and PVB appeared to be very similar, whereas that of MOVB was slower. The uptake/dose trend was also similar four all four drugs tested and conelated to the levels of lipophilicity of the agents.
Confocal microscopy studies showed all the photosensitizers to be distributed widely throughout the cytoplasm, with considerable accumulation of VBBO and PVB in the perinuclear region. Time course studies showed the intracellular distribution of VBBO in both cell lines to be similar, although uptake of the drug appeared slower in the resistant cell line. VBBO was clearly localised throughout the cytoplasm, in a punctate pattern, which may be consistent with the widespread distribution of mitochondria. No interaction with the plasma membrane was evident. By contrast, doxorubicin was found to localise mainly in the nucleus of the sensitive cell line, whereas no nuclear involvement was seen in the resistant cells. The drug was also effluxed more rapidly from EMT6-R cells than EMT6-S cells. Time course studies with EMT6-S cells showed that the drug clearly interacts with both the plasma membrane and the nucleus. These results indicate that the main modes of action for the two drugs differ markedly, suggesting interaction with both the membrane and the nucleus in the case of doxorubicin, but possibly mitochondrial involvement for VBBO
The Development of an Academic Literacies Programme for Students in Britain and Beyond
Richmond’s Academic Literacies Programme (ALP) is a content-based form of instruction for university students which teaches critical reading, research skills, content synthesis, and writing and presentation skills. It is designed to empower all students to research and write effectively throughout their undergraduate studies. This article is a quantitative case study review of a British-American university’s ALP, examining student feedback across academic disciplines on specific taught ALP skills and comparing their improvement from 2014 to 2022. Chi-squared goodness-of-fit tests showed students valued research, critical reading, academic writing, essay structure, understanding academic honesty, using tutor feedback, and referencing skills; however, survey development and recommendation reports were not meeting student needs in their majors and so were removed from the programme. In comparison, in a follow-up review conducted in 2022, the skill of identifying research gaps was not effectively used or applied. However, independent group testing found the usefulness of skills at the lower learning level improved from 2014 to 2022, as did the application of skills at the higher level. This study concludes that ALPs are valuable for all university students beginning higher education research, regardless of first language or degree course
Social media use improves executive functions in middle-aged and older adults: A structural equation modeling analysis
Estudio de la entrada mediante comercio electrónico de empresas españolas en el mercado chino, de alimentos para mascotas
[ES] En este trabajo se analiza la posibilidad de que las empresas españolas ingresen al mercado chino de alimentos para mascotas a través del comercio electrónico. Se utiliza el siguiente procedimiento: primero, analizar el macroambiente chino; segundo, estudiar el mercado chino de alimentos para mascotas y la industria española de alimentos para mascotas, con el fin de comparar las ventajas y desventajas de las empresas españolas si entran en este mercado; al final, se sugiere una estrategia de marketing-mix para ingresar al mercado chino. Los resultados señalan que la entrada en el mercado chino de alimentos para mascotas es posible y beneficiosa para las empresas españolas de alimentos para mascotas que deseen expandir su negocio.[EN] This work analyzes the possibility of Spanish companies entering the Chinese pet food market through E-commerce. This work uses the following procedure: first, analyze the Chinese macroenvironment; second, study the Chinese pet food market and the Spanish pet food industry, in order to compare the advantage and disadvantage of Spanish companies if they enter this market; in the end, suggest a marketing-mix strategy for entering the Chinese market. The results indicate that entry into the Chinese pet food market is possible and beneficial for Spanish pet food companies who want to expand their business.Wang, S. (2020). Estudio de la entrada mediante comercio electrónico de empresas españolas en el mercado chino, de alimentos para mascotas. Universitat Politècnica de València. http://hdl.handle.net/10251/153185TFG
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